﻿<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>
     <script src="//code.jquery.com/jquery-1.11.0.min.js"></script>
    <script src="//code.jquery.com/jquery-migrate-1.2.1.min.js"></script>
    <script>
        $('.enableToggle').on('keyup paste', function () {
            var curVal = $(this).val().replace(/\s+/g, '').length > 0;
            $(this).siblings('.enableToggle').prop('disabled', curVal);
        });
    </script>
 
</head>
    <body>
  <form>
    <div>
        <label for="downpayment">Downpayment</label>
        <input name="downpayment" class="enableToggle" id="downpayment" type="text" style="width:250px" />
        <label for="full_payment">Full payment</label>
        <input name="full_payment" class="enableToggle" id="full_payment" type="text" style="width:250px" />
    </div>
</form></body>
</html>
